Technical Field
The present technique relates to the field of data processing. More particularly, it relates to generating an estimate of the reciprocal of an operand or reciprocal of the square root of an operand.
Background
There are a number of data processing operations for which it is useful to provide, as a starting point, an estimate of a reciprocal of an operand, or an estimate of a reciprocal of the square root of the operand. For example, the Newton-Raphson method for division may use an estimate of the reciprocal of the divisor as its starting point. Also, when calculating the actual reciprocal or reciprocal of the square root of an operand, an iterative process such as the Newton-Raphson method may yield the result faster if starting with an estimate of the reciprocal or the reciprocal square root. Therefore, providing a reciprocal estimation operation for generating reciprocal estimates and reciprocal square root estimates is useful for a range of operations. Sometimes, the reciprocal estimate may be useful in its own right—e.g. if the full precision of the full reciprocal operation is not required, then the reciprocal estimate can provide a faster result. The present technique seeks to provide improved circuitry for performing the reciprocal estimation operation.